Display device, apparatus for generating gamma voltage, and method for the same

Abstract

A display device includes a display unit including a plurality of pixels connected to a plurality of data lines, a data driver selecting a grayscale voltage according to an image data signal among a plurality of gamma voltages to apply the grayscale voltage to the plurality of data lines, a gamma voltage generator generating a plurality of gamma voltages; and a reference voltage generator generating a reference voltage to generate a plurality of gamma voltages in cooperation with a power source voltage to drive the plurality of pixels.

What is claimed is: 
     
         1 . A display device, comprising:
 a display unit including a plurality of pixels connected to a plurality of data lines;   a data driver selecting a grayscale voltage according to an image data signal among a plurality of gamma voltages to apply the grayscale voltage to the plurality of data lines;   a gamma voltage generator generating a plurality of gamma voltages; and   a first reference voltage generator generating a reference voltage to generate a plurality of gamma voltages in cooperation with a power source voltage to drive the plurality of pixels.   
     
     
         2 . The display device of  claim 1 , wherein the first reference voltage generator registers a voltage difference between a first power source voltage and a first reference voltage in the process of predetermining the gamma voltage, and generates a second reference voltage as a differential value between a second power source voltage and the registered voltage difference. 
     
     
         3 . The display device of  claim 2 , wherein the first reference voltage generator includes:
 a voltage difference generator including a plurality of resistors coupled in series between a reference voltage and a ground voltage;   a voltage difference selection unit selecting and outputting a voltage corresponding to a voltage difference between the first power source voltage and the first reference voltage among a plurality of distribution voltages distributed to a plurality of resistors; and   a reference voltage output unit outputting a differential value between the second power source voltage and the voltage output from the voltage difference selection unit as the second reference voltage.   
     
     
         4 . The display device of  claim 3 , wherein a plurality of resistors included in the voltage difference generator have a resistance determined for a plurality of distribution voltages to be distributed as a predetermined unit. 
     
     
         5 . The display device of  claim 3 , wherein the voltage difference selection unit registers a voltage difference between the first power source voltage and the first reference voltage in the process of predetermining the gamma voltage, and outputs the registered voltage difference to the reference voltage output unit after producing a product. 
     
     
         6 . The display device of  claim 3 , wherein the reference voltage output unit includes a differential amplifier outputting a differential value between a power source voltage supplied from the outside and the voltage output from the voltage difference selection unit. 
     
     
         7 . The display device of  claim 1 , wherein the gamma voltage generator includes:
 a reference voltage division unit including a plurality of resistors coupled in series between the reference voltage and the base voltage;   a gamma voltage selection unit selecting a plurality of gamma voltages corresponding to a predetermined grayscale by using a plurality of distribution voltages distributed to a plurality of resistors; and   a gamma voltage output unit outputting a plurality of gamma voltages corresponding to an entire grayscale by using the reference voltage provided from the reference voltage generator and a plurality of gamma voltages selected from the gamma voltage selection unit.   
     
     
         8 . The display device of  claim 7 , wherein the gamma voltage selection unit includes a first selector selecting a second gamma voltage representing a gray level higher than the first gamma voltage corresponding to the reference voltage by one. 
     
     
         9 . The display device of  claim 8 , wherein the gamma voltage selection unit further includes a second selector selecting a seventh gamma voltage as a lowest voltage among a plurality of gamma voltages corresponding to the entire grayscale. 
     
     
         10 . The display device of  claim 9 , wherein the gamma voltage selection unit further includes a sixth selector selecting a sixth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the seventh gamma voltage selected from the second selector. 
     
     
         11 . The display device of  claim 10 , wherein the gamma voltage selection unit further includes a fifth selector selecting a fifth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the sixth gamma voltage selected from the six selector. 
     
     
         12 . The display device of  claim 11 , wherein the gamma voltage selection unit further includes a fourth selector selecting a fourth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the fifth gamma voltage selected from the fifth selector. 
     
     
         13 . The display device of  claim 12 , wherein the gamma voltage selection unit further includes a third selector selecting a third gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the fourth gamma voltage selected from the fourth selector. 
     
     
         14 . The display device of  claim 7 , wherein the gamma voltage generator further includes a micro-controller providing a register value for minute control of the gamma voltage to the gamma voltage selection unit. 
     
     
         15 . The display device of  claim 1 , further comprising a second reference voltage generator generating a base voltage to generate a plurality of gamma voltages in cooperation with a power source voltage to drive a plurality of pixels. 
     
     
         16 . The display device of  claim 15 , wherein the second reference voltage generator registers a voltage difference between a first power source voltage and a first base voltage in the process of predetermining the gamma voltage, and generates a second base voltage as a differential value between a second power source voltage and the registered voltage difference. 
     
     
         17 . The display device of  claim 16 , wherein the second reference voltage generator includes:
 a first differential amplifier including a first input terminal input with the reference voltage and an output terminal outputting the amplifying voltage;   a voltage difference generator including a plurality of resistors coupled in series between the amplifying voltage and a ground;   a voltage difference selection unit selecting a distribution voltage from the voltage difference generator to output an amplifying voltage corresponding to a voltage difference between the first power source voltage and the first base voltage from the first differential amplifier and to input the distribution voltage to the second input terminal of the first differential amplifier; and   a base voltage output unit outputting a differential value of the second power source voltage and the amplifying voltage as a second base voltage.   
     
     
         18 . The display device of  claim 17 , wherein the voltage difference selection unit registers the amplifying voltage corresponding to the voltage difference between the first power source voltage and the first base voltage in a process of generating the gamma voltage, and the registered amplifying voltage is output through the first differential amplifier after producing the product. 
     
     
         19 . The display device of  claim 17 , wherein the base voltage output unit includes a second differential amplifier that outputs a differential value of a power source voltage supplied from the outside and an amplifying voltage output from the first differential amplifier. 
     
     
         20 . A gamma voltage generating apparatus, comprising:
 a reference voltage generator registering a voltage difference between a first power source voltage to drive a plurality of pixels and a predetermined first reference voltage in a process of predetermining a gamma voltage, and generating a second reference voltage as a differential value between a second power source voltage to drive a plurality of pixels and the registered voltage difference; and   a gamma voltage generator generating a plurality of gamma voltages by using the second reference voltage.   
     
     
         21 . The gamma voltage generating apparatus of  claim 20 , wherein the first reference voltage generator includes:
 a voltage difference generator including a plurality of resistors coupled in series between a reference voltage and a ground voltage;   a voltage difference selection unit selecting and outputting a voltage corresponding to a voltage difference between the first power source voltage and the first reference voltage among a plurality of distribution voltages distributed to a plurality of resistors; and   a reference voltage output unit outputting a differential value between the second power source voltage and the voltage output from the voltage difference selection unit as the second reference voltage.   
     
     
         22 . The gamma voltage generating apparatus of  claim 21 , wherein a plurality of resistors included in the voltage difference generator have resistances determined for a plurality of distribution voltages to be distributed as a predetermined unit. 
     
     
         23 . The gamma voltage generating apparatus of  claim 21 , wherein the voltage difference selection unit registers a voltage difference between the first power source voltage and the first reference voltage in the process of predetermining the gamma voltage, and outputs the registered voltage difference to the reference voltage output unit after producing a product. 
     
     
         24 . The gamma voltage generating apparatus of  claim 21 , wherein the reference voltage output unit includes a differential amplifier outputting a differential value between the second power source voltage and the voltage output from the voltage difference selection unit. 
     
     
         25 . The gamma voltage generating apparatus of  claim 20 , wherein the gamma voltage generator includes:
 a reference voltage division unit including a plurality of resistors coupled in series between the second reference voltage and the ground voltage;   a gamma voltage selection unit selecting a plurality of gamma voltages corresponding to a predetermined grayscale by using a plurality of distribution voltages distributed to a plurality of resistors; and   a gamma voltage output unit outputting a plurality of gamma voltages corresponding to an entire grayscale by using the second reference voltage and a plurality of gamma voltages selected from the gamma voltage selection unit.   
     
     
         26 . The gamma voltage generating apparatus of  claim 25 , wherein the gamma voltage selection unit includes a first selector selecting the second gamma voltage representing a gray level higher than the first gamma voltage corresponding to the second reference voltage by one. 
     
     
         27 . The gamma voltage generating apparatus of  claim 26 , wherein the gamma voltage selection unit further includes a second selector selecting a seventh gamma voltage as a lowest voltage among a plurality of gamma voltages corresponding to the entire grayscale. 
     
     
         28 . The gamma voltage generating apparatus of  claim 27 , wherein the gamma voltage selection unit further includes a sixth selector selecting a sixth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the seventh gamma voltage selected from the second selector. 
     
     
         29 . The gamma voltage generating apparatus of  claim 28 , wherein the gamma voltage selection unit further includes a fifth selector selecting a fifth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the sixth gamma voltage selected from the six selector. 
     
     
         30 . The gamma voltage generating apparatus of  claim 29 , wherein the gamma voltage selection unit further includes a fourth selector selecting a fourth gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the fifth gamma voltage selected from the fifth selector. 
     
     
         31 . The gamma voltage generating apparatus of  claim 30 , wherein the gamma voltage selection unit further includes a third selector selecting a third gamma voltage by using a distribution resistor connected to the second gamma voltage transmitted from the first selector and the fourth gamma voltage selected from the fourth selector. 
     
     
         32 . The gamma voltage generating apparatus of  claim 20 , further comprising a second reference voltage generator generating a base voltage to generate a plurality of gamma voltages in cooperation with a power source voltage to drive a plurality of pixels. 
     
     
         33 . The gamma voltage generating apparatus of  claim 32 , wherein the second reference voltage generator registers a voltage difference between a first power source voltage and a first base voltage in the process of predetermining the gamma voltage, and generates a second base voltage as a differential value between a second power source voltage and the registered voltage difference. 
     
     
         34 . The gamma voltage generating apparatus of  claim 33 , wherein the second reference voltage generator includes:
 a first differential amplifier including a first input terminal input with the reference voltage and an output terminal outputting the amplifying voltage;   a voltage difference generator including a plurality of resistors coupled in series between the amplifying voltage and a ground;   a voltage difference selection unit selecting a distribution voltage from the voltage difference generator to output an amplifying voltage corresponding to a voltage difference between the first power source voltage and the first base voltage from the first differential amplifier and to input the distribution voltage to the second input terminal of the first differential amplifier; and   a base voltage output unit outputting a differential value of the second power source voltage and the amplifying voltage as a second base voltage.   
     
     
         35 . The gamma voltage generating apparatus of  claim 34 , wherein the voltage difference selection unit registers the amplifying voltage corresponding to the voltage difference between the first power source voltage and the first base voltage in a process of generating the gamma voltage, and the registered amplifying voltage is output through the first differential amplifier after producing the product. 
     
     
         36 . The gamma voltage generating apparatus of  claim 34 , wherein the base voltage output unit includes a second differential amplifier that outputs a differential value of a power source voltage supplied from the outside and an amplifying voltage output from the first differential amplifier. 
     
     
         37 . A method of generating a gamma voltage, the method comprising:
 registering a voltage difference between a first power source voltage to drive a plurality of pixels and a predetermined first reference voltage in the process of predetermining the gamma voltage;   generating a second reference voltage as a differential value between a second power source voltage to drive a plurality of pixels and the registered voltage difference after producing a product; and   generating a plurality of gamma voltages by using the second reference voltage.   
     
     
         38 . The method of  claim 37 , wherein registering the voltage difference includes selecting a voltage corresponding to a voltage difference between the first power source voltage and the first reference voltage among a plurality of distribution voltage distributed to a plurality of resistors coupled in series between the reference voltage and the ground voltage. 
     
     
         39 . The method of  claim 37 , further comprising registering a second voltage difference of the first power source voltage to drive a plurality of pixels and a predetermined first base voltage in the process of predetermining the gamma voltage. 
     
     
         40 . The method of  claim 39 , further comprising generating a second base voltage as a differential value of the second power source voltage to drive a plurality of pixels and the registered second voltage difference after producing a product. 
     
     
         41 . The method of  claim 40 , wherein generating a plurality of gamma voltages includes generating a plurality of gamma voltages by using the second reference voltage and the second base voltage. 
     
     
         42 . The method of  claim 37 , wherein generating a plurality of gamma voltages includes:
 selecting a plurality of gamma voltages corresponding to a predetermined grayscale by using a plurality of distribution voltages distributed to a plurality of resistors coupled in series between the second reference voltage and the ground voltage; and   generating a plurality of gamma voltages corresponding to an entire grayscale by using the second reference voltage and a plurality of gamma voltages corresponding to the predetermined grayscale.   
     
     
         43 . The method of  claim 42 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting the second gamma voltage representing a gray level higher than the first gamma voltage corresponding to the second reference voltage. 
     
     
         44 . The method of  claim 43 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting a seventh gamma voltage as a lowest voltage among a plurality of gamma voltages corresponding to the entire grayscale 
     
     
         45 . The method of  claim 44 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting a sixth gamma voltage by using a distribution resistor connected to the second gamma voltage and the seventh gamma voltage. 
     
     
         46 . The method of  claim 45 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting a fifth gamma voltage by using a distribution resistor connected between the second gamma voltage and the sixth gamma voltage. 
     
     
         47 . The method of  claim 46 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting a fourth gamma voltage by using a distribution resistor connected between the second gamma voltage and the fifth gamma voltage. 
     
     
         48 . The method of  claim 47 , wherein selecting a plurality of gamma voltages corresponding to a predetermined grayscale includes selecting a third gamma voltage by using a distribution resistor connected between the second gamma voltage and the fourth gamma voltage.